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Fewer cyclones but bleak future for reef

Evan Schwarten

Australia will see fewer cyclones in the future as a result of climate change but the outlook is increasingly bad for the Great Barrier Reef.

Scientists are meeting in Cairns this week to discuss the latest developments in climate science at the biennial CSIRO Greenhouse 2011 conference.

Among the new research is some relatively good news - the expected rise in global temperature is expected to result in a drop in the number of cyclones affecting Australia each year.

University of Melbourne Meteorologist Associate Professor Kevin Walsh said his research into changes in tropical cyclones predicted a 20 per cent drop in the number of cyclones affecting Australia by 2100.

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He said the reduction would be more or less uniform but there would also be a corresponding increase of about five per cent in the strength of some cyclones.

"Overall there appears to be fewer cyclones but the most intense ones appear to be getting more intense," he told reporters.

The research may be seen as a positive in cyclone prone regions such as far north Queensland which was recently battered by Cyclone Yasi.

However, many scientists presented a bleak outlook for the future - especially regarding the Great Barrier Reef.

University of Queensland climate change researcher Professor Ove Hoegh-Gulberg said rising sea temperatures and the acidisation of oceans due to increasing carbon levels would kill the reef if there wasn't a dramatic drop in emissions within the next decade.

"We are going to get into a situation where reefs will no longer be able to sustain themselves," he told the conference.

"If we don't achieve those lower levels of CO2 in the atmosphere and have no more than a two-degree rise in sea temperature we will not have the Great Barrier Reef to crow about."

Professor Hoegh-Gulberg said hopes that coral reefs may migrate south to cooler waters as temperatures rise or could evolve to suit the changing conditions were overly optimistic.

He said coral was a slow evolving species and reefs would need to migrate south at a rate of about 15 kilometres an hour to survive - where a migration rate of one kilometre a century was more realistic.